The present application is related generally to infusion pumps for the delivery of fluids to a patient. More particularly, embodiments of the invention disclose rugged, pre-filled mechanical or elastomeric pumps that are suitable for storage and transportation in a field bag and for immediate use on an injured patient, where the elastomeric or mechanical infusion pump expels fluids under pressure.
Typical IV fluid delivery devices rely on a bag of fluids, which is then infused with additional medications, whether it be to treat pain, administer antibiotics, or otherwise administer fluids or medication to a patient. These IV fluid bags require elevation for gravity feeding of fluids, typically through the use of an IV stand, or other feature to hold the IV bag at a proper elevation to provide consistent pressure for the delivery of these fluids. In a hospital setting, this is not a large issue as an IV stand can easily be situated near a patient's bed or an electronic infusion pump can be utilized. However, even in hospital environments, this IV stand then must be carted with a patient as the patient is moved. Furthermore, the IV stand is another apparatus that adds clutter to a hospital room.
Electronic infusion pumps may solve some of the issues related to gravity fed delivery of fluids. However, many circumstances are present where electronic infusion pumps are not practical or feasible. There is an unmet need for a rugged infusion pump suitable for use in circumstances where electronic infusion pumps are unavailable.
In situations where no IV stand is available, and where no electronic source is available for use of an electronic infusion pump, for instance in a combat zone, or away from a hospital setting, when a patient is wounded and requires IV fluids, another person is often required to hold and elevate the IV bag to allow for the delivery of fluids. Having a person hold the IV bag wastes the resources of that person and also creates an inconsistent pressure source, as the IV bag is likely to be constantly moving.
Conventional elastomeric pumps are fragile, complicated to use, and are designed for insertion by highly trained medical professionals. These devices are typically meant for the delivery of small amounts of pain medication and are installed during a surgical process. These pumps are also typically delicate and not designed for use during turbulent transportation or during strenuous movement by a patient. Furthermore, these devices are seldom pre-filled with sterile fluids for immediate use. Instead, elastomeric pumps in the prior art are typically filled right before use, and are not capable of prolonged storage under pressure.
Elastomeric pumps, for example Hessel, U.S. Pat. No. 4,915,693 provides an elastomeric bladder infusion pump for delivering a pharmaceutically active material. However, Hessel requires the elastomeric bladder to be filled with a volume of fluids and medications for immediate use and contains no pump housing.
Lasonde et al., U.S. Pat. No. 5,529,214 describes an elastomeric pump that contains a pump housing, but again requires that the bladder be filled on the spot. Further, Lasonde et al. requires the use of a mandrel to be inserted into the hosing and secured to the housing and the bladder.
Burns et al., U.S. Pat. No. 6,413,239, describe an improved infusion pump that, like Hessel and Lasonde, must be filled on the spot. Further, Burns et al. requires the use of an insertion member that stretches the elastomeric bladder in a radial, but not axial direction and a cap that seals one end of a balloon.
Heston et al, U.S. Pub. No. 2006/0229558, Oct. 12, 2006, describes an elastomeric infusion pump and an axially-variable core positioned within the bladder. Again the liquid is supplied by an external source at the point of infusion.
The prior art contains products that are inefficient, inaccurate, and possess inadequate pressure. IV bags are inefficient as they need to be elevated at a consistent height to provide for consistent and accurate delivery of fluids via gravity. In a location without an IV stand, typically another person would be required to hold an IV bag at a consistent height, which lacks the consistency and accuracy necessary for delivery of IV fluids and wastes human resources in combat situations.
IV bags are also consistently inefficient. They require manual regulation and measurement of flow. Fluid flow is typically measured by counting drops as they drip into a drip chamber from an IV bag. The flow rate can change based on the height of the bag. Regulating flow requires manual manipulation of a thumbwheel that is typical with IV bags, and requires recalibration when a patient moves, or when the height of the bag is changed.
Inaccuracies also plague IV bags. Any change in the position of the IV bag, movement by a patient, or change in venous pressure can drastically alter the flow rate of fluids from the IV bag to a patient. Accordingly, a trained medical advisor must frequently monitor IV bags to ensure that flow is within accepted ranges of the fluids being delivered.
Further, IV bags often lack adequate pressure for a fast flow rate or for I/O insertion. This requires a medical advisor or other person to manually squeeze an IV bag to provide sufficient pressure, again, wasting time and resources.
The prior art provides for elastomeric and or gravity devices that are to be filled on the spot by a medical practitioner and are not designed to store fluids under pressure for an extended period of time, and therefore are not suitable for immediate use within the field. Nor are these devices rugged enough for storage and use in medical field bags within military combat zones. Furthermore, these devices are typically used for very slow infusion, i.e. over the course of a number of days, utilizing low total volumes. Additionally, traditional drip IV devices are inefficient, inaccurate, and lack adequate pressure for many IV uses, especially outside of a medical facility. There is not a suitable solution for a rugged, pre-filled elastomeric or mechanical infusion pump capable of storing fluids under pressure for up to two years and suitable for being carried into the battle field and used on the spot without the need to fill the bladder, for delivery of fluids to a patient.